Email URL Links - Add a user customizable dropdown list

I find myself cutting and pasting the same 6 or 8 common URL links when emailing customers. It would be a nice productivity gain if I could define those URL links in a list, within my user account and then, on the Insert/Edit popup window, have a combo-box that would allow entering a custom URL, or allow clicking the down arrow to select from the common ones I have pre-defined.